Line edge roughness and critical dimension variation

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Technological Educational Institute of Athens
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2004 (EN)
Line edge roughness and critical dimension variation (EN)

Leunissen, Leonardus H. A. (EL)
Πάτσης, Γεώργιος (EL)
Γογγολίδης, Ευάγγελος (EL)
Κωνσταντούδης, Βασίλειος (EL)

N/A (EN)

Line edge (or width) roughness (LER or LWR) of photoresists lines constitutes a serious issue in shrinking the critical dimensions (CD) of the gates to dimensions of a few tens of nanometers. In this article, we address the problem of the reliable LER characterization as well as the association of LWR with the CD variations. The complete LER characterization requires more parameters than the rms value σ since the latter neglects the spatial aspects of LER and does not predict the dependence on the length of the measured line. The further spatial LER descriptors may be the correlation length ξ and the roughness exponent α, which can be estimated through various methods. One aim of the present work is to perform a systematic comparative study of these methods using model edges generated by a roughness algorithm, in order to show their advantages and disadvantages for a reliable and accurate determination of the spatial LER parameters. In particular, we compare the results from (a) the study of the height–height correlation function (HHCF), (b) the Fourier [or power spectrum (PS)] analysis, and (c) the variation of rms value σ with measured line edge L [σ(L) curve]. It is found that the HHCF can be considered approximately a rescaled version of σ(L) and that the value of σ becomes almost independent of the measured edge length for lengths larger than ten times the correlation length. As regards the PS, it is shown that the finite length of the edge may harmfully affect the reliable estimation of α and ξ. Finally, we confirm theoretically and generalize an experimental observation [Leunissen et al., Microelectron. Eng. (to be published)] regarding the relationship between LWR and the σ of the CD variations within a die of a wafer. It is shown that they behave in a complimentary way as line length increases so that the sum of their squares remains constant and equal to the square of the LWR σ of the infinite line. (EN)


Φωτοαντίσταση (EN)
Photoresistance (EN)
Διαστάσεις χώρου (EN)
Applied physics (EN)
Εφαρμοσμένη φυσική (EN)
Spatial dimensions (EN)

ΤΕΙ Αθήνας (EL)
Technological Educational Institute of Athens (EN)

Journal of Vacuum Science & Technology B (EN)



DOI: 10.1116/1.1776561

American Vacuum Society (EN)

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